Communication system



July 20, 1943. N. H. REEVE COMMUNICATION SYSTEM Filed June 7. 1941 2 Sheets-Sheet 2 L -J K wi/h Patented July 20, 1943 COMMUNICATION SYSTEM Norman H. Reeve, Racine, Wis., assignor to Webster Electric Company, Racine, Wis., a corporation of Delaware Application June 7, 1941 Serial No. 397,117.

22 Claims.

The present invention relates to communication systems and more particularly to a new and improved system of program distribution from a central station to a plurality of outlying stations, combined with means for paging the outlying points from the central station.

One of the objects of the present invention resides in the provision of a new and improved system of program distribution.

A further object of the invention is the proision of a new and improved system of program distribution and monitoring, and likewise in the provision of an arrangement whereby the monitor speaker is utilizable to test the operation of various amplifiers included in the system.

A fiuther'objcct' of' the present invention resides. in the provision of a new and improved arrangement for automatically cutting out the monitor speaker when announcements are. being made locally, thereby to prevent feed-back.

A further object of the present invention resides in the provision of anew and improved arrangement for calling all the outlying stations, which stations may be connected to either of two program channels or foff channel,v and in which a monitor speaker is cut out to prevent feed-back when the stations aresocalledr Another object of the invention is to provide a new and improved arrangement for calling a plurallty of outlying stations wherein an emergency call switch is provided to take precedence over program selector switches and, wherein the call is sent to all stations even though theoutput of the amplifiers included in the system is disconnected from the channels and connectedto a monitor speaker. j Other objects-and a lvantages of the present invention will become apparent from the ensuing description, in the course of which reference is had to theaccompanying drawings in which Figures 1 and 2' are partial diagrammatic representations of one embodiment of the invention. Thetwo figures, when laid side by side, illustrate the apparatus at the central station as a whole. V v V 5 Referring now to the figures, it may be noted that the central station equipment is indicated as a whole by reference character Hi. The outlying stations have not beenillustrated, but each of these has three channels leading to it from the central station. lwo of these channels, in,-

dicated by reference characters I and 2,"are

program channels and the third channel 3 is the previously referred to oil channel. The outlying stations each have a loud speaker and a selector switch for connecting the loud speaker to any of the threechannels. The speaker and selector switches may be arranged as illustrated in the ctr-pending application of Richard H. Campbell, Serial No. 397,098, filed June 7, 19-51, assigned to the assignee of this application.

Before proceeding with a detailed description of the circuit arrangement, it may be well briefly to consider the salient elements of the system.

There are a plurality of program sources which and a remotely located microphone is connected to a pro-amplifier l8.

In addition, there is provided a local microphone it (that is, one located at the central station) connected to a pre-amplifier 22 through which announcements may be made to stations over each or both-of the channels and which is also used for calling all the stations.

The apparatus atthe central station includes two banks 24 and 26 of program selector switches and an emergency-call switch 23, preferably of the key type. The former are operable to connect the program sources to an input circuit 30 leading to channel I, and an. input circuit 32 leading to channel 2, except when the emergency call witch 28 is operated. When the'latter is operated, relays 34 and. 35 are effective toconnect the local microphone 26 directly to both in- ;put circuits.

The input circuits 3i) and 32 lead to apparatus included within the dotted lines 34 and 36, al-. though that within the latter has not been illustrated as it is identical with that in the former which is associated with input circuit 38. The

input circuit 3?! leads to a driver amplifier 38, the output of which is connected directly through a driver amplifier test key 40 to the inputs of power amplifiers 42, 44, and 46, connected in. parallel.

The outputs of the latter are connected through test keys 4%, 5i], and 52 to an output bus line 54.

The output bus line leads to a monitor test jack 56, to a monitor control switch 58, and to a monitor control relay 69. The monitor speaker is indicated bythe referencecharacter B2 and it is connected through a circuit 64 to a monitor switch 65, the purpose and functioning of which will be described hereinafter;

Channel I is connected to the monitor control switch 58, through a branch circuit 66 to the monitor control relay, and through another branch circuit I to a relay 12 operable simultaneously with relays 34 and 36 to connect in parallel channels I, 2, and 3.

Returning now to a detailed description of the circuits, and particularly to Figure l and the program sources, it may be noted that the phonograph I2 is connected through a circuit 14 to key switches 16 and 18 in the banks of switches 24 and 26, respectively. The studio I4 is similarly connected through circuit 80 to key switches 82 and 84. Radio RI is connected directly to key switch 66 in bank 24, and radio R2 is connected to key switch 88 in bank 25. It may be seen, therefore, that the radio programs may be supplied only to the circuits to which the two banks of switches 24 and 26 are connected, namely, channels i and 2, respectively. The remotely located microphone I6 is connected through circuit 90 to key switches 92 and 64 in the banks of switches 24 and 26, respectively. The local microphone 20 is connected to key switches 96 and I00 in the respective banks, through a circuit including conductors I02, the normally closed key switch I04 of the emergency call switch 28, and conductors I06 and I08.

The key switches associated with all the sources except the local microphone and the emergency call switch are all identical and comprise pairs of fixed and movable blades. The switches associated with the local microphone include, in addition to the pairs of fixed and movable blades, a third fixed and movable blade defining switches IIO and H2 controlling the monitor relay 60 associated with channel I, and a similar relay associated with channel 2 in the manner hereinafter to be described. All the switches of bank 24 are connected to a common circuit II4 connected to input circuit through the movable switch blades I I6 and fixed blades II8 of relay 34. In like manner, the movable blades of the switches of bank 26 are connected to a common circuit I20, connected to input circuit 32 through the movable and fixed blades I22 and I24 of relay 36.

When the emergency call switch is operated, the local microphone 20 is disconnected from its associated switches in banks 24 and 26 by switch I04, and is connected to both input circuits 30 and 32 through circuit I26, the fixed and movable switch blades I28 and I I6 of relay 34, and the fixed and movable switch blades I30 and I22 of relay 36. The emergency call switch when operated is effective to energize the windings I34 and I36 of the relays 34 and 36, as well as the winding I38 of the output paralleling relay 12 which is connected in parallel with the former through a circuit I40. This energization of the relay windings is effected by movable switch blade I42 of the call switch. The windings of the monitor control relays 60 are energized at the same time through a circuit including the movable switch blade I44 of the emergency call switch.

The three first mentioned relays are connected upon operation of the emergency call switch to power lines I46 through the switch blade I42. The positive terminal of the power source is connected by conductor I48 to movable switch blade I42 and thence to one terminal of each of the relay windings to conductor I50. The other terminal of each winding is connected to the negative terminal of the power supply by conductor I52. The windings I54 of the monitor control relays 60 are connected to the source of power upon operation of the emergency call switch through circuit I56, one conductor of which is connected directly to the negative power supply line, and the other to a conducto I58 connected to the fixed switch blade I58 associated with movable switch blades I44. Th latter is connected through conductor I48 to the positive power supply line. The conductor I58 is connected also to the fixed blades associated with the movable blades H0 and H2 of the switches controlling the connection of the local microphone to the input circuits. The movable blades H0 and H2 are connected by a conductor I62 to the conductor I48 leading to the positive power supply line. It may be seen, therefore, that the monitor control relays are energized when the local microphone is used either a program source over one or the othe of the channels, or for making an emergency call to all the stations.

The amplifier test keys 40, 46, 50, and 52, and the monitor key 66 are provided for the purpose f testing the driver and power amplifiers. To test the driver amplifier 38, the test key 45! is depressed, thereby disconnecting the output of the driver amplifier from the inputs of the power amplifiers and connecting it to a driver test jack I64 adapted to receive a suitable instrument for indicating the output of the driver amplifier.

To test the power amplifiers, it is necessary to operate the monitor key 66 at the same time as the test key of the particular amplifier is operated. The amplifier test keys normally connect their respective amplifier outputs to the common output bus line 54 and, when depressed, connect the output to a test line I66 bridged by a load resistor I68. When the monitor key 66 is de pressed, the test line I66 is connected to circuit 64 and thence through a volume control 10 and a transformer I12 to the monitor speaker 62. The described arrangement provides a simple and easily operable arrangement for testing the outputs of the various amplifiers.

The monitor control switch 58 normally connects the common output bus line 54 to channel I through the simultaneously movable switch blades I14 and the associated fixed switch blades I16. At this time, the monitor speaker is disconnected both from the channel I and from the common output bus line. If it is desired to connect the monitor speaker to the output bus line, the movable switch blades I14 are moved upwardly into contact with the fixed switch blades I18. When so operated, the channel I is disconnected from the output bus line and the latter is connected to the monitor speaker through the movable and fixed switch blades just referred to, circuit I leading to the monitor control relay 60, the movable blades I62 and fixed blades I84 of the latter, and a circuit I86 leading to the monitor key 66 and the speaker circuit 64. When it is desired to connect the monitor speaker to both the output bus line and to channel I, the simultaneously movable switch blades I88 of the monitor control switch 58 are brought into engagement with the fixed contacts I90. The former are connected to the bus line and the latter to circuit I00 and thence through the contacts of the monitor control relay 60 to the monitor speaker as just described.

When the emergency call switch is operated, the monitor speaker is cut out by the relay 60,

The latter disconnects the monitor circuit l86 from the monitor control switchby disengagement of blades I82 and IM, and connects the output-bus line 54 to channel I through the fixed and movable blades 192 and I94, and the branchcircuit 68-. The same'result is obtained wheneverthe local microphone is used since the monitor control relays are operated'also upon actuation of the switches for connecting the local microphone to either one or both of the channels; i I a When the emergency call switch is operated, it will be remembered that the output paralleling relay i2 is also operated.- This relay, when op} erated, serves to parallel channels I, 2, and 3 so that the local microphone Z is connected to all threechannels through thesets' of amplifier associated with both channels I and Z.

From the foregoing detailed description of the circuits, it may be noted that the central station is normally conditioned tojtransmitei'ther programs or announcements 'over either or both channels. Assuming, for instance, that it is desired to place a radioprogram obtainable from radio RI on channel I, and a program obtain able from radio R,2 on channel 2, then it is simply necessary for the operator at the central station to close switches 86 and 88, respectively. The radio programs are thereby supplied to the channels through the input circuit, thedriver and power amplifiers, the output bus line, and the monitor control switch associated with each of the channels. In a similar manner, the phonograph, studio program, or program announcements obtainable through the remotely located microphone I6 may be supplied on either or both channels since these program sources are connected to switches in both banks of switches 24 and 26. Announcements maybe likewisesent over the local microphone over channel I by operation of switch 56, or over channel 2 by operation of switch H2. When either of these switches is operated, the local microphone is connected to the output line through the same circuits as the programs and, at the same time, both the monitor control relays 60 are operated thereby to disconnect the monitorspeakers: in case the monitor control switches 58, are in positions connecting the monitor speakers either to over the other program sources so that it is not necessary to operate any of the switches asso ciated with the latter when it isdesired to make an emergency call. When the emergency call switch is operated, the local microphone is connected to both input circuits'3t and 32 upon operation of relays 34 and 36. At the same time, the program sources are disconnected by operation of the relay. Thegemergency call switch also energizes the monitor relays 80 and the output paralleling relay 12 through circuits previously described. As a consequence, an emergency call may bemade without regard to the position of the other program selector switchesand through both channels so that the call iszheard at the outlying stationsirrespective-of whether .the

tern, the combination loudspeakers thereat areconmeted to channel I, channel 2, or the oil channel 3. .i Theemergencycall is rem te the outlyin stations also,- even speaker alone'beconnectedto mam This takes place "as a result oi' -the-operation or the monitor comma relays ",the sameas'when the local microphone isus'edthrohgh'ene ol the normal'channels.

- a While only-s singleembodimcnt of the present invention has-been described, it should be understood' that this embodinmt is not to be mm strued as-limi'tative ofthe invention but merely as'illustrativeofits principles, and that the scopeof theinvention is defined in the appended claims. 5 Having thus described what"! claimas new and desire to by Letters Pat entof theUnitedstates is:

' I. Ina program distributingand calling system, "the combination including, amplifying means, switch means for selectively connecting program sources to said amplifying means, a calling rjnicrophone; and means including s switcn and a. relay controlled thereby for disconnecting a selected program source from said amplifying means and connecting said microphone thereto.

'2. In a program distributing and calling system, the combination including, amplifying means, a calling microphone, switch" means for selectively connecting program sources or said microphone to said amplifying means through one circuit, and means including other smtch means and a relay controlled thereby for d'iscon necting said firstmentioned switch means from said amplifyingfmeansand connecting said imcrophone to said amplifying means through another circuit.

SrIn a program distributing and calling system, the combination 1 including, amplifying means'in one channel, amplifying means in another channel, switch meansassociated with each channel-- for connecting program sources to the amplifying means in said channels, a calling microphone; andmeansincmding a switch and relays controlled thereby for disconnecting selected program sourcesfrom safdamplifymg means and connecting said microphone to the" amplifying meansin both'sai'd manneisfi I 4. In a pro-gramoistributfng and calling sys'-' 7 including, "amplifying means in one channel, ampiiiyingmea'ns' in an otherchannel; switch means associated with each channel for connecting program sources to the amplifyingmean's in said channels, a calling microphone, means including a switch and relays controlled thereby for disconnecting selected program. sources from said amplifying means and connecting said microphone to the amplifying means in both said channels, and .meansincluding another relay controlled by said switch for connecting in parallel the output ends of both said channels'.'

'5. In a program distributing system,the combination including, a; distributing channel including amplifying means, an 01f channel, switch means associated with said distributing channel for connecting program sources to said amplifying means, a calling microphone, means includ-- ing a switch, and a relay controlled thereby tor disconnecting. selected program soureeszfrom said amplifying means: and connecting microphone thereto, and means includinganotherrelaywcontrolled bysaid switchfor fofi channel to the ing channel. I H

. 6., In a program distributingand calling sys tem, the combination including, first andsecond distributing. channels each including amplifying means, switch means associated with each channel-forconnecting program sources to the amplifying means in said channels, an off channel, a calling microphone, means including a switch and relays controlled thereby for disconnecting selected program sources from said amplifying means and connecting said microphone to the amplifying means in both said channels, and means includin another relay controlled by said switch for connecting in parallel said off channel and the output ends of said distributing channels g 7. Ina program distributing and calling system, the combination including, first and second distributing channels each including amplifying means, a calling 'microphone, means including switches. associated with, each channel for connecting programsources or said calling microphone. to the amplifyingmeans through channel input circuits, and means including a switch and relays controlled thereby for disconnecting said. switches from said amplifying means and connecting sai'd calling microphone to both amplifying ineansthrough another circuit.

'8.A' system according to claim '7, including another relay controlled .by said last mentioned switch operable to connect in parallel the output endsof both'said channels. I

'9. A system according to'claim '7, including an off channel and, another relay controlled by said last mentioned'switch for connecting in parallel the "off "chan'nel and the output ends of both of said distributing'channels.

10. Ina program distributing system, the combination. including, a distributing channel including amplifying means, a monitor loudspeaker connected to the output of said amplifying means'afmicrophon located in proximity to said loudspeaker, switch means for connecting said microphone to said amplifying means, and means including a relay controlled by said switch means for simultaneously disconnecting said' loudspeaker from sai'doutput.

11. In a program distributing system, the combination including, a distributing channel including amplifying means, a monitor loudspeaker connected to the outputof said amplifying means andto-the output end of said channel, a microphone located infproximity to said loudspeaker,

output end of said distributswitch means forconnecting said microphone to said amplifyingv means, and means including a relay controlled by said switch means for simultaneously disconnecting said loudspeaker from said output and output e'nd'of'said channel.

' 12. In a program distributing system, the combinationincludihga distributing channel including 'amplifying means, a 'monitor loudspeaker, switch means" operable 'to connect said loudspeakerto the outputof said amplifying means or to bothsaid output an'd'to the output end of said channel, a microph'one located in proximity to said loudspeaker; switch means for connecting saidmicrophone' tosaid amplifying means, and means including a relaycontrolled by said switch means for simuitaneously disconnecting said loudspeaker from both said output and the outbut end ofsaid channel and connecting said output to'the output end of said channel.

13. Ina-program distributingsystem, the combination-including. a distributing channel including amplifying means, a monitor loudspeaker connected to the output of said amplifying means, a microphone located in proximity to said loudspeaker, switch means for connecting said microphone to said amplify'mg means, and means including a relay controlled by said switch means for simultaneously disconnecting said loudspeaker from said output and for connecting said output to the output end of said channel,

14. In a program distributing and calling system, the combination including, first and second distributing channels each including amplifying means, manitor loudspeakers connected to the outputs of each of said amplifying means, a microphone located in proximity to said loudspeakers, separate switch means for selectively connecting said microphone to the amplifying means in both channels, and means including relays controlled by each of said switch means for simultaneously disconnecting both said loudspeakers from said outputs.

15. In a program distributing and calling system, the combination including, first and second distributing channels each including amplifying means, monitor loudspeakers connected to the outputs of each of said amplifying means, a microphone located in proximity to said loudspeakers, separate switch means for selectively connecting said microphone to the amplifying means in both channels, and means including relays controlled by each of said switch means for simultaneously disconnecting both said loudspeakers from said outputs and connecting each of said outputs to the outgoing end of its distribution channel.

16. In a program distributing and calling system, the combination including, first and second distributing channels each including amplifying means, monitor loudspeakers for each channel, separate switch means operable to connect said loudspeakers either to the output of the amplifylng means or to said output and the outgoing end of its associated channel, a microphone located in proximity to said loudspeakers, other switch means for connecting said micophone to the amplifying means in either channel, and means including relays controlled by said other switch means for connecting the outputs of both of said amplifying means to the outgoing ends of their respective channels.

17. In a program distributing and calling system, the combination including, first and second distributing channels each including amplifying means, monitor loudspeakers connected to the outputs of each of said amplifying means, a microphone located in proximity to said loudspeakers, switch means for selectively connecting said microphone to the amplifying means of either of said channels, other switch means for connecting said microphone to the amplifying means of both said channels, irrespective of the positions of said first switch means, and means including relays associated with each loudspeaker controlled by both said switches for disconnecting both said loudspeakers from said outputs.

18. In a program distributing and calling system, the combination including, first and second distributing channels each including amplifying means, monitor loudspeakers connected to the outputs of each of said amplifying means, a microphone located in proximity to said loudspeakers, switch means for selectively connecting said microphone to the amplifying means of either of said channels, other switch means for connecting said microphone to the amplifying means of both said channels, irrespective of the positions of said first switch means, and means including relays associated with each loudspeaker controlled by both said switches for disconnecting both said,

loudspeakers from said outputs and simultaneously connecting said outputs to the outgoing ends of their respective channels.

19. In a program distributing and calling system, the combination including, first and second distributing channels each including amplifying means, monitor loudspeakers for each channel, switch means associated with each connecting in one position the outputs of the amplifying means to the outgoing end of its associated channel, said switch means being operable to a second position to connect said loudspeakers to the outputs or to a third position to connect said loudspeakers to both the outputs and outgoing ends of said channels, a microphone located in proximity to said loudspeakers, switch means for selectively connecting said microphone to the amplifying means of each of said channels, other switch means for connecting said microphone to the amplifying means of both said channels irrespective of the positions of said second switch means, and means including relays in said channels controlled by said second and third switch means for disconnecting said loudspeakers and connecting the outputs of the amplifying means to the outgoing ends of said channels irrespective of the position of said first switch means.

20. In a program distributing and calling system, the combination including, first and second distributing channels each including an input 9 circuit, amplifying means, an output bus line and an outgoing circuit,,an ofi channel, a local microphone, other program sources, selector switches in each channel for connecting said program sources or local microphone to the input circuits of either or both amplifying means, the connections to each of said amplifying means including a relay having normally closed switches, said relays also having normally open switches for providing alternate connections to the input circuits, said switches being connected to the local microphone, other switch means normally connecting said local microphone to its said selector switches and operable in an emergency call position to disconnect said local microphone from its selector switches, said other switch means including means for operating said relays in its emergency call position, whereby said microphone is connected to the input circuits of both said amplifying means, monitor loudspeakers for each channel, monitor contro1 switch means located between the bus line and outgoing circuit of each of the distributing channels, said switch means connecting the bus lines to the outgoing circuits in one position, connecting the monitor speaker to the bus lines only in a second position and connecting the monitor speaker to the interconnected bus lines and outgoing circuits in a third position, a monitor speaker control relay in each channel having normally closed switches for connecting the monitor speaker to monitor control switch means, which switches are opened upon operation of the relays, and having normally open switches closable on operation of the relays to connect the bus lines to their associated channel outgoing circuits, said monitor control relays being operable upon operation of the selector switches connecting the local mirophone ,to either of said amplifying means or upon operation of said other switch to connect said microphone to both said amplifying means, whereby the monitor speakers are cut out by opening of the normally closed switches of the relays to prevent feed back, and the bus lines are connected directly to the outgoing ends of their respective channels irrespective of the position of the monitor control switch means, and a relay having normally open switch means for connecting in parallel said distributing and off channels, said relay being operable to close said switch means by said emergency call switch, whereby, when the latter is operated, all three channels are connected in parallel to the outputs of the amplifying means in the two distributing channels.

21. In a sound amplifying system, the combination including, a plurality of amplifiers having their outputs connected to a common line, switch means in each of said connections normally completing said connections and operable to connect said outputs to a second common line, a monitor loudspeaker, switch means normally disconnecting said loudspeaker from said second common line and operable to connect it thereto, whereby the outputs of said amplifiers may be selectively directed to said loudspeaker by operating said last mentioned switch means and the switch means individual to the amplifiers.

22. In a sound amplifying system, the combination including, a plurality of amplifiers having their outputs connected to a common line, switch means in each of said connections normally completing said connections and operable to break said connections and to connect said outputs to a second common line, a monitor loudspeaker, switch means normally connecting said loudspeaker to said first common line and operable to connect it to said second common line, whereby the monitor loudspeaker is normally connected to the common output of all said amplifiers and may be connected to the outputs of the individual amplifiers by operating said last mentioned switch means and the switch means individual to the amplifiers.

NORMAN H. REE-VE. 

